Plate-shaped external storage device and method of producing the same

ABSTRACT

An external storage device includes a storage medium series element containing at least a non-volatile memory device and external connection terminals connected to input/output terminals of the storage medium series element. An insulator molds the series element and terminals into a plate to form a plate-shaped external storage device. The terminals may be exposed in concavities or in a plane on a peripheral surface of the external storage device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to external storage devices capable of recordingand saving various data, a method of producing the external storagedevices, an external storage device unit. More specifically, theinvention relates to an external storage device exchangeably used forstorage equipment and devices as an external storage medium, a method ofreadily producing the external storage device, and an effectiveutilization of the external storage device.

2. Description of the Related Art

Storage devices or memory elements, which are capable of recording andsaving various data, have been utilized in two systems. In one systemthey are incorporated and fixed within storage equipment or devices, andin the other system they are releasably or exchangeably incorporated inthe storage equipment or devices. For the external storage devices theymay optionally be attached or detached or freely removed from thestorage equipment or devices, for example, floppy disk devices can beattached and detached by one touch operation. Therefore, when floppydisks are the recording mediums they can separately be used, dependingon the purpose and object, to record and save the data, whereby easierdata reduction can advantageously be obtained.

However, a problem arises in the floppy disks described above, when thedata occasionally disappears during data recording or saving producingless reliability in addition to slower access time. In addition whenproducing smaller sized floppy disks in response to a miniaturizationpolicy, a storing area of the storage medium is correspondingly smallerto reduce storage capacity, this thus limits practical use thereof.

On the other hand, semiconductor memory devices used as external storagedevice such as IC memory cards can overcome the drawbacks in floppydisks, because they generally exhibit graded reliability of datarecording and saving and relatively rapid access time.

The IC memory cards comprise, a functional circuit in which circuitcomponents containing the semiconductor memory devices or elements aremounted on substrates, a resin casing attached therein with thefunctional circuit as an inside attachment, a cover for coating andsealing both opening surfaces of the resin casing, and externalconnection terminals such as two piece connectors which are attached onone edge of the resin casing and electrically connect the functionalcircuit and the storage equipment/device. However, IC memory cards areassembled with a large amount of components and parts, where arelatively complicated structure is required with limitation to athickness of the IC memory card. Further, disadvantages arise as aresult of lower cost performance or production yields on mass productionin addition to the lower releasability for the storage equipment/devicesor fluctuated releasability on function.

SUMMARY OF THE INVENTION

An object of the invention is to provide an external storage deviceformed by a simplified process.

Another object of the invention is to provide an external storage devicehaving a high releasability with a high reliable function as an externalstorage medium.

Further, another object of the invention is to provide a method ofproducing a highly reliable external storage device with gradedproduction yields.

Still another object of the invention is to provide an external storagedevice unit formed by a simplified process.

Still further, another object of the invention is to provide an externalstorage device unit having a high releasability with a reliable superiorfunction as an external storage medium.

An external storage device according to the present invention ischaracterized by comprising,

an external storage device molded into a plate shape or a card shapethrough coating and sealing a storage medium series element containingat least a non-volatile semiconductor memory device by using insulator,and

external connection terminals connected to input/output terminals of thestorage medium series element coated, incorporated by the insulator andled and exposed in a concaved or plane manner on a peripheral surface ofthe external storage device main.

An external storage device unit according to the invention ischaracterized by comprising:

an external storage device formed into a plate shape through unitarilycoating and sealing the storage medium series element containing atleast a non-volatile semiconductor memory device by insulator, and anexternal storage device having external connection terminals connectedto the input/output terminals of the storage medium series elementcoated and incorporated unitarily by the insulator and led and exposedin concaved manner on a peripheral surface of the external storagedevice main; and

an external storage device unit including, an engaging section contactedand engaged with a concaved surface led and exposed of at least theexternal connection terminals of the external storage device, and aconnection section having electric contacts which are arranged on amated contact surface of the engaging section and which are resilientlyconnected and disconnected from the external connection terminalsdepending on engaging, attaching and detaching of the external storagedevice for the engaging section.

Alternatively, an external storage device unit according to theinvention includes:

an external storage device formed of, an external storage device mainmolded into a plate shape through unitarily coating and sealing anexternal medium series element containing at least a non-volatilesemiconductor memory device by an insulator, and external connectionterminals which are connected to input/output terminals of the storagemedium series element coated and incorporated by the insulator and whichare led and exposed on a peripheral surface of the external storagedevice main; and

an external storage device unit main including an engaging sectionengaged and contacted with a surface led and exposed of at least theexternal connection terminals of the external storage device, aconnection section having electric contacts which are arranged on amated contact surface of the engaging section and which are resilientlyconnected or disconnect from the external connection terminals dependingon engaging, attaching, or detaching of the external storage device tothe engaging section, and a circuit having a control circuit and aninterface circuit for the external storage device to be engaged,attached and detached. Here, the external storage device unit main maypreferable be formed into a card shape.

A method of producing an external storage device according to theinvention is characterized by comprising the steps of: process in whichan external medium series element containing at least a non-volatilesemiconductor memory device electrically connected with concaved typeexternal connection terminals led outside is arranged in a splitting andassembling type mold provided on its inside walls with protruded shapedterminal protrusions respectively in corresponding to the externalconnection terminals led outside in way that the external connectionterminals and the protruded shaped terminal protrusions opposing eachother are registered;

process in which sealing resin is injected into mold arranged andregistered of the storage medium series element and both the storagemedium series element and the concaved type external connectionterminals led outside are coated and sealed unitarily by insulativeresin to be formed into a plate shape; and

process in which after molding by the mold, mold pieces of splitting andassembling type are allowed to separate from a plate shaped mold state.

The present invention has cleverly been conceived in that asemiconductor memory device or element is mounted on the conventionalsubstrate, on the other hand, the invention has been achieved in view ofthe fact that, when a NAND type flash memory device or element (NANDtype flash E² ROM) comes to have a higher integration than DRAM (dynamicrandom access memory) with a capacity of 16 M-bits per chip, it cancorrespond to 2 M-bytes of floppy disk. In the structure of the externalstorage device with a plate shape or a card shape according to theinvention, a part or entire of the control circuit components such assemiconductor elements forming a control function in addition to thenon-volatile semiconductor memory device exhibiting a memory function,are incorporated into the plate shaped or card type external storagedevice to produce a build-in type.

In the external storage device according to the invention, first, amemory capacity of an extent of 16 M-bits per chip can be obtainedbecause of a high integration, thereby the non-volatile semiconductormemory device is used as a main memory without requiring a power supplyfor maintaining the storage. Secondly, the main memory is made intounitary forms, the plate shape or the card type by insulative resin etc.This mold type readily provides easier handling, simplified structure ina thin shape, resulting in lower cost. In addition, the externalconnection terminals are provided in concaved or flat shapes to enablethe mold structure of the external storage device to maintain andexhibit higher releasability for the storage equipment/device and toraise a reliability of electrical connection or disconnection due toattaching or detaching operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing essentials of an example of anexternal storage device according to the invention;

FIG. 2 is a perspective line plan view showing essentials of an exampleof an external storage device according to the invention;

FIG. 3 is a schematic sectional view showing essentials of a preferredembodiment in producing an external storage device according to theinvention;

FIG. 4 is a schematic sectional view showing essentials of anotherpreferred embodiment in producing an external storage device accordingto the invention;

FIG. 5 is a perspective view showing a broken down example of an outlineof an external storage device unit according to the invention;

FIG. 6 is a perspective view showing a broken down example of essentialsof an external storage device unit according to the invention;

FIG. 7 is a perspective view showing a broken down example of essentialsof another external storage device unit according to the invention;

FIG. 8 is a perspective view showing an example of a different structureof an external storage device unit according to the invention; and

FIG. 9 is a perspective view showing an example of a further anotherstructure of an external storage device unit according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

FIG. 1 is a perspective illustration of an outline of an example of anexternal storage device according to the invention, and FIG. 2 is aperspective line plan view of an outline of an example of an externalstorage device according to the invention. In this embodiment, anexternal storage device 1 is configured in that a NAND type flash memorydevice 2 is made up on a frame substrate by a wire bonding method toproduce a main body thereof sized with a length of 40 mm and a width ofabout 30 mm. The external storage device main is formed into a thinplate shape, coated, and mold sealed by a generally used semiconductorelement molding resin such as epoxy based resin or the like. The NANDtype flash memory device 2 may be bonded by a TAB (Tape AutomatedBonding) system. In this embodiment, on input/output portions of theNAND type flash memory device 2, recessed external connection terminals5 are electrically connected by a wire bonding 4 these terminals 5 areled and exposed, in a manner of slightly formed recessed surfaces 5a, onend surfaces of opposing edges in the thin plate shape by the coatingand sealing.

In a method of producing the external storage device, FIGS. 3 and 4 aresectional views schematically showing a preferred embodiment of a methodof producing the external storage device. First, the control proceeds toprepare the NAND type flash memory device 2 to be provided with therequired external connection terminals 5. An example of this NAND typeflash memory device 2 to be prepared is of a NAND type. The device 2 isassembled in that the recessed shaped external connection terminals 5are electrically connected and led outside by a wire bonding system. TheNAND type flash memory device 2 is attached on a metallic frame (notshown) and may preferably be fixed tentatively with a lead 5b which isled outside. On the other hand, the control proceeds to prepare for adisassemble type mold provided on its predetermined inside-walls with aprotruded terminal shaped protrusion 6a mated with a recessed surface 5aof each recessed shaped external connection terminal 5 which is ledoutside, with respect to the NAND type flash memory device 2. The mold 6is formed into a disassemble type and includes a side wall 6b formed bycombining squared side-walls, a bottom wall 6c engaging and sealingsquared top and bottom openings formed from the side walls 6b, and a topwall 6d. A pair of side walls 6b they oppose each other from among theside walls 6b are arranged with a group of terminal shaped protrusions6a opposing each other for corresponding to the recessed surfaces 5a ofthe external connection terminals 5 of the NAND type flash memory device2.

The disassemble type mold 6 registers, engages, and arranges theexternal connection terminals 5 of the NAND type flash memory device 2with the corresponding terminal shaped protrusions 6a of the mold 6.Then if required, the NAND type flash memory device 2 is floated andpositioned through supporting pieces (not shown) for the bottom walls 6cof the mold 6. A concrete example thereof includes supporting both aframe section for loading the NAND type flash memory device 2 and theexternal connection terminals 5 on the mold 6 by using thin frame bars.In this way, after positioning and arranging the NAND type flash memorydevice 2 within the mold 6, the control proceeds to inject sealing resin3, such as epoxy resin, to coat and seal the NAND type flash memorydevice 2 together with the recessed shaped external connection terminals5 in unitary shape with the insulative resin 3, and form a plate shape.Thereafter, the walls or mold pieces 6b, 6c, and 6d of the assembled andformed mold 6 are separated from each other and from the plate shapedmold to produce the external storage device as shown in FIGS. 1 and 2.

In FIGS. 1 and 2, numeral 1a depicts a mark for indicating direction ofthe external storage device 1, showing the mechanical attaching andconnection for the storage equipment/device and preventing or avoidingerroneous attaching. The mark 1a showing directionality is not limitedto a corner section or one corner, but it may preferably be set tosimultaneously provide a guide function in a detachable structure of theequipment/devices. A connection for the external connection terminals 5of the external storage device 1 may preferable be non-contactconnection systems such as radio waves or lights in addition tomechanical connections.

Embodiment 2

FIGS. 5 to 7 are perspective views showing outlines of structurestogether with operation modes of an external storage device unitaccording to the invention. In this example, the external storage device1 formed as described above in the embodiment 1 is in a condition ofhaving a one-side constituent element. The storage medium series elementcontaining at least the non-volatile semiconductor memory chip 2 iscoated and sealed by the insulator 3, such as epoxy resin, to beconnected with the input/output terminals of both the card shape moldedexternal storage device and the storage medium series element coated andincorporated by the insulator 3. This produces the external storagedevice 1 having external connection terminals 5 exposed in the manner ofa concaved surface on a periphery end surface of the external storagedevice main, where such external storage device 1 is premised on thisembodiment. As shown in FIG. 5, when inserting or extracting theexternal storage device 1 in or from the engage type unit 7 of thestorage equipment/device main by one touch operation, depending on suchinsertion or extraction, the external connection terminal 5 led andexposed on opposing edges is resiliently connected to or disconnectedfrom an electric contact 8 arranged on an engaging section of theengaging unit 7.

FIG. 6 shows in detail a structural example of the engaging unit 7,where opposing surfaces of a pair of supporters 7a and 7a', arranged tooppose each other, are engaged with end surfaces from the externalconnection terminals 5 of the external storage device 1 to produce aslidable form. Electric contacts 8 corresponding to the externalconnection terminals 5 of the external storage device 1 are electricallyand insulatively arranged on a slidably formed region on the opposingsurfaces of the supporters 7a and 7a'. These electric contacts 8 areelectrically connected to the main body-side of the storageequipment/device and form the necessary electric circuit.

Numeral 7b depicts a slide stop member of the external storage device 1for sliding the opposing surfaces of the pair of supporters 7a and 7a'.When the external storage device 1 is inserted and tip end thereofcontacts the slide stop member 7b, pin type springs 7c and 7c' rotate inopposite directions by pressure due to such contact. By the rotation ofthe pin type springs 7c and 7c', the electric contacts 8 arranged on theopposing surfaces of the supporters 7a and 7a' contact withcorresponding external connection terminals 5 of the thus insertedexternal storage device 1 to achieve necessary electrical connection.Here, an automatic fixing and setting are completed by inserting theexternal storage device 1 into the engaging unit 7 to attach it in apredetermined position. Depressing a push button (not shown) arranged ona main body of the unit provides for release of a fixed engaging piece(not shown) and extraction of the external storage device 1. Onreleasing the fixed engaging piece, the external storage device 1 isautomatically extracted by the reverse rotation of the pin type springs7c and 7c' and the contacts of the external connection terminals 5 andthe electric contacts 8 are released.

According to the invention, the engaging unit 7 is formed asdevelopmentally shown in FIG. 7, where the pair of supporters 7a and 7a'may preferable be arranged to be movable in opposite direction through aresilient type springs 7d by a pair of cylinders 7e and 7e'respectively. Even in this structure, the electric contacts 8, whichcorrespond to the external connection terminals 5 led and exposed onopposing end surfaces of the external storage device 1, are electricallyinsulated with each other and arranged on opposing surfaces of thesupporters 7a and 7a'. Of course, these electric contacts 8 areelectrically connected to the storage equipment/device main body sideand form the necessary electric circuit. Numeral 7b' depicts aninsertion stop member when the external storage device 1 is inserted.When the external storage device 1 is inserted to contact the externalstorage device 1 with the insertion stop member 7b', pressure of thiscontact rotates the resilient type springs 7c and 7c' reverse to anenergizing direction. This rotation forwards the supporters 7a and 7a'in opposite directions to press and contact the electric contacts 8 tothe corresponding external connection terminals 5 of the thus insertedexternal storage device 1 to achieve the required electric connection.On the other hand, when extracting the external storage device 1, thepin type springs 7c and 7c' are reversally rotated, and it iscorrespondingly pushed out. As is the case shown in FIG. 6, the externalstorage device 1 is inserted into the engaging unit 7 and attached in apredetermined position, then an automatic fixed setting is performed. Onreleasing the fixed setting, it is automatically pushed out by thereverse rotation of the pin type springs 7c and 7c', and the contacts ofboth the external connection terminals 5 and the electric contacts 8 arereleased.

Embodiment 3

FIGS. 8 and 9 are perspective views showing different examples ofexternal storage device units according to the invention respectively.In the drawings, the external storage device 1 constructed as follows isin a one-side constituent element. The storage medium series elementcontaining at least a non-volatile semiconductor memory chip is coatedand sealed by an insulator, to be connected with input/output terminalsof both an external storage device main formed in a card shape and astorage medium series element incorporated with coating of theinsulator. This produces an external storage device 1 having externalconnection terminals 5 led and exposed in a manner of a concaved orplane shape on the peripheral end surface or the main surface of theexternal storage device main, where such external storage device 1 ispremised on this embodiment. The external storage device 1, as shown inFIGS. 8 and 9, can optionally be attached or detached to or from anexternal storage device unit main 9 provided with a region or window 9acapable of attaching and detaching the external storage device 1. Theexternal storage device unit main 9 including a control device for theexternal storage device 1 is combined with a connection section formedof electric contacts for resiliently connecting or disconnecting to orfrom the external connection terminals 5 depending on whether theexternal storage device 1 is attached or detached to or from the region9a. The region 9a is a window forming an engaging/attaching section andis to be detachable from the external storage device 1. As in the otherembodiments described, the external storage device 1 is engaged,attached and detached by one touch operation to and form theengaging/attaching section or region 9a of the external storage deviceunit main 9 to produce the required functions such as recording etc.

In the structure in FIG. 8, the electric contacts 8 corresponding to theexternal connection terminals 5 of the external storage device 1 areresiliently provided on the engaging/attaching section 9a of theexternal storage device unit main 9. On engaging, attaching and settingthe external storage device 1, a pressure force thereof allows theelectric contacts 8 to resiliently contact with the external connectionterminals 5 led and exposed in a plane manner on the main surface(backside surface) of the external storage device 1, and such re-addedpressure resets the external storage device 1. Upon detachment theelectric contacts 8 are simultaneously resiliently detached from theexternal connection terminals 5.

In FIG. 9, when the external storage device 1 is engaged, attached, andset on the engaging/attaching section 9a of the external storage deviceunit main 9, the external connection terminals 5, which are placed onthe end surface in the attaching or inserting direction, resilientlycontact with the electric contacts 8 arranged on a contact surface ofthe engaging/attaching section 9a. Preferably, the electric contacts 8are resiliently provided on the side connection section. On resetting toengage or attach the external storage device 1, engaging or hooking isreleased and this allows the electric contacts 8 to detach from theexternal connection terminals 5. If the external storage device unitmain is formed into a card shape, then preferably, the external storagedevice unit is easy to carry as a set. The conventional card typeexternal storage device, so called an IC memory card functions as one ICmemory card such that pin connections are loaded in accordance withJEIDA (Japanese Electric Industry Development Association) or PCMCIA(Personal Computer Memory Card International Association), or the othersemiconductor devices such as interface circuits or semiconductor memorycontrol circuits or switching circuits are loaded on the substrate. Onthe contrary, in the present invention only the semiconductor memory isoptionally separated and used, this therefore provides a greatadvantage.

Preferably, the connecting section of the above embodiments includes acircuit having a memory circuit, an interface circuit, and a switchingcircuit for the external storage device 1.

It is understood that the invention is not limited to the embodiments asdescribed above and in the foregoing. Various changes may be madetherein without departing from the subject matter of the invention.

As hereinbefore fully described, in the external storage device and theexternal storage device unit according to the invention, variousadvantages are provided as listed below. For the external storagedevice, a high integration is provided, where the non-volatilesemiconductor memory device having a larger memory capacity even in onecompact chip is used as a main memory, which is molded unitarily into acard shape by insulative resin etc. Such use of the unitary mold typeand the non-volatile semiconductor memory device readily providesoptional detaching, easier carrying, easier handling, and thin compactstructure, and thus resulting in lower cost performance. In the unitaryform thereof, since the external connection terminals are made into aconcaved surface or a flat surface without protruding from the coated orsealed resin layer surface, an upgraded slidability is obtained, thiseliminates damage and erroneous connection of the external connectionterminals.

The external storage device unit also exhibits graded releasability andimproved reliability in function. In particular, various advantages inpractical use of the external storage device unit include optionaldetaching of the external storage device, easier carrying without thepossibility of damage from the outside, and a larger recording/savingcapacity of the data even in a compact size.

What is claimed is:
 1. An external storage device unit comprising:aplate-shaped external storage device including: a non-volatilesemiconductor memory device including input/output terminals, externalconnection terminals connected to the input/output terminals, theexternal connection terminals having end surfaces, and an insulatorcoating and sealing the memory device and the external connectionterminals unitarily into a molded plate to form a plate-shaped externalstorage device, the end surfaces of the external connection terminalsbeing exposed in concavities on a peripheral surface of the plate-shapedexternal storage device; and a connection section including:an engagingsection disposed opposite from the peripheral surface of theplate-shaped external storage device for attachment and detachment toand from the external storage device, the engaging section mating andcontacting with the end surfaces of the external connection terminals ofthe external storage device, and electric contacts on a surface of theengaging section for resilient connection to and disconnection from theexternal connection terminals, depending on whether the engaging sectionattaches or detaches with the external storage device.
 2. An externalstorage device unit as claimed in claim 1, wherein the non-volatilesemiconductor memory device is a NAND type flash memory device.
 3. Anexternal storage device unit as claimed in claim 1, wherein theinsulator is epoxy resin.
 4. An external storage device unit as claimedin claim 1, wherein the engaging section has a plate-shape having a sidesurface and a main surface.
 5. An external storage device unit asclaimed in claim 4, wherein the electric contacts are resilientlyprovided on the side surface of the engaging section, and wherein theperipheral surface is the side surface of the plate-shaped externalstorage device so that the external connection terminals electricallyconnect with the electric contacts.
 6. An external storage device unitas claimed in claim 4, wherein the electric contacts are resilientlyprovided on the main surface of the engaging section, and wherein theperipheral surface is the main surface of the plate-shaped externalstorage device so that the external connection terminals electricallyconnect with the electric contacts.
 7. An external storage device unitcomprising:a plate-shaped external storage device including:anon-volatile semiconductor memory device including input/outputterminals, external connection terminals connected to the input/outputterminals, the external connection terminals having end surfaces, and aninsulator coating and sealing the memory device and the externalconnection terminals unitarily into a molded plate to form aplate-shaped external storage device, the end surfaces of the externalconnection terminals being exposed in a plane on a peripheral surface ofthe plate-shaped external storage device; and a connection sectionincluding:an engaging section disposed opposite from the peripheralsurface of the plate-shaped external storage device for attachment anddetachment to and from the external storage device, the engaging sectionmating and contacting with the end surfaces of the external connectionterminals of the external storage device, and electric contacts arrangedon a surface of the engaging section for resilient connection to anddisconnection from the external connection terminals depending onwhether the engaging section attaches or detaches with the externalstorage device.
 8. An external storage device unit as claimed in claim7, wherein the non-volatile semiconductor memory device is a NAND typeflash memory device.
 9. An external storage device unit as claimed inclaim 7, wherein the insulator is epoxy resin.
 10. An external storagedevice unit as claimed in claim 7, wherein the engaging section has aplate shape having a side surface and a main surface.
 11. An externalstorage device unit as claimed in claim 10, wherein the electriccontacts are resiliently provided on the side surface of the engagingsection, and wherein the peripheral surface is the side surface of theplate-shaped external storage device so that the external connectionterminals electrically connect with the electric contacts.
 12. Anexternal storage device unit as claimed in claim 10, wherein theelectric contacts are resiliently provided on the main surface of theengaging section, and wherein the peripheral surface is the main surfaceof the plate-shaped external storage device so that the externalconnection terminals electrically connect with the electric contacts.13. An external storage device unit comprising:a plate-shaped externalstorage device including:a non-volatile semiconductor memory deviceincluding input/output terminals, external connection terminalsconnected to the input/output terminals, the external connectionterminals having end surfaces, and an insulator coating and sealing thememory device and the external connection terminals unitarily into amolded plate to form a plate-shaped external storage device, the endsurfaces of the external connection terminals being exposed on aperipheral surface of the plate-shaped external storage device; and anexternal storage device unit main includingan engaging section disposedopposite from the peripheral surface of the plate-shaped externalstorage device for attachment and detachment to and from the externalstorage device, the engaging section mating and contacting with the endsurfaces of the external connection terminals of the external storagedevice, electric contacts arranged on a surface of the engaging sectionfor resilient connection to and disconnection from the externalconnection terminals depending on whether the engaging section attachesor detaches with the external storage device, and a circuit having amemory control circuit, an interface circuit and a switching circuit forthe external storage device.
 14. An external storage device unit asclaimed in claim 13, wherein the non-volatile semiconductor memorydevice is a NAND type flash memory device.
 15. An external storagedevice unit as claimed in claim 13, wherein the insulator is epoxyresin.
 16. An external storage device unit as claimed in claim 13,wherein the engaging section has a plate shape having a side surface anda main surface.
 17. An external storage device unit as claimed in claim16, wherein the electric contacts are resiliently provided on the sidesurface of the engaging section, and wherein the peripheral surface isthe side surface of the plate-shaped external storage device so that theexternal connection terminals electrically connect with the electriccontacts.
 18. An external storage device unit as claimed in claim 17,wherein the end surfaces of the external connection terminals areexposed in concavities on the peripheral surface of the plate-shapedexternal storage device.
 19. An external storage device unit as claimedin claim 17, wherein the end surfaces of the external connectionterminals are exposed in a plane on the peripheral surface of theplate-shaped external storage device.
 20. An external storage deviceunit as claimed in claim 16, wherein the electric contacts areresiliently provided on the main surface of the engaging section, andwherein the peripheral surface is the main surface of the plate-shapedexternal storage device so that the external connection terminalselectrically connect with the electric contacts.
 21. An external storagedevice unit as claimed in claim 20, wherein the end surfaces of theexternal connection terminals are exposed in concavities on theperipheral surface of the plate-shaped external storage device.
 22. Anexternal storage device unit as claimed in claim 20, wherein the endsurfaces of the external connection terminals are exposed in a plane onthe peripheral surface of the plate-shaped external storage device.